How do I chain shape keys?
If you add two shape keys without the new shape key from mix option, you can animate them separately. It is Important is that you keyframe the 2nd part of the animation with influence 0 for the duration of the first part. This way the 2nd part does not start before it is supposed to do.







Editing the shape for extrusion: In Edit Mode a loopcut is added at the top of the extruded cube to create the geometry required for the second part of the animation.